Part of the main issue with pd creeping is shields, and with shields come the main issue of their insane regen rates (talking 600 health per second) given t3 artillery does effectively 75 damage per second there is no real mass effective counter to a strong pd/shield push. Especially when t3 pds come into play.
Last game i encountered a t3 push I made 6 TML launchers and simply hit the enemy acu making t3 pds (I guess he thought he was safe under a shield) during which time i made 4 t3 mobile artillery to slow the crawl, but it felt ineffective at best. Even the TML's weren't really mass effective and it required my enemy acu not noticing. Hardly fine strategic play is it
It is something the balance team are looking into for 3612 and onwards.